Evaluation of current methods for processing bloody fingerprints on non-porous substrates exposed to various contaminants

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https://hdl.handle.net/2144/23762

Abstract

Blood is a common type of medium with which patent fingerprints are deposited at crime scenes. Chemical enhancements are generally used on bloody fingerprints when some type of pattern is visible but ridge characteristics are not sufficiently defined to make the print suitable for comparison. Motor vehicles, which may be associated with crimes scenes or forensic investigations, can be exposed to a variety of contaminants from the environment, including mud, salt, pollen, dust and motor oil, as well as from the application of chemicals to protect the paint such as car wax and car polish. It is unknown if these contaminants in combination with the chemicals used to enhance bloody impressions or in combination with the blood itself, could impact the enhancement of bloody impressions found on vehicles. This study seeks to assess the effectiveness of a selection of blood enhancement methods in the presence of such contaminants. Three of the four enhancement chemicals that were tested, Amido Black, Hungarian Red, and Leucocrystal Violet, were determined to be similarly effective for the enhancement of bloody friction ridge patterns applied to the surfaces of contaminated glass and metal substrates.